So Ive got a customer wanting a sign 45" wide and I was just wondering if anyone has come up with a way to cut oversized pieces as the shapeoko xxl max cutting width is 33". Would love to get some ideas and feedback on this.

You have to build points into your design to use as index points so that you have a know set of points to start the second half of the job. I've seen some folks us pins (dowels) on the backside with corresponding holes in the bed. Others have 2 or 3 points in the design that they line the bit up with to make sure it's lined up and square.

I would test my setup on some cheap stock before going at it for reals. Especially if it's my first go at it.